Asbestos/cement or plastic (PVC) high pressure pipes are presently in widespread use. These pipes are usually distributed with an annular collar at one end of each pipe in press fit with the pipe, and with the other end of each pipe tapered slightly to be received telescopically in the collar of an adjacent aligned pipe when a pipeline is being formed.
In the assembly of such a pipeline, it is necessary for each pipe to be pulled in the direction of the aligned collar until its tapered end extends into the collar. Since the pipes are extremely heavy and since considerable force is required to draw them together, more force is required than workmen can readily exert directly on the pipes, especially when the pipes are at the bottom of a trench, which is usually the case. Therefore, various devices have been devised in the prior art to provide the necessary mechanical advantage to enable the workmen to draw the pipes together. It is necessary that such devices apply little, if any, lateral force to the pipes as they are drawn together in order to maintain the pipes in alignment.
As mentioned above, it is the usual practice to assemble the pipes at the bottom of a trench. The width of the trench is made as narrow as possible to reduce costs. Thus the device used to assembly the pipes should be compact in size in order to accommodate this minimum trench width, and must also lend itself to operation while in the trench.
Devices capable of joining pipes under the conditions outlined above are known to the art. Such devices are disclosed, for example, in Simmons U.S. Pat. No. 3,096,572 and in Wilkerson U.S. Pat. No. 3,571,896. However, although these devices do perform the required functions, they are still somewhat difficult to operate, and often require several persons to operate the devices and assemble the pipeline, especially when heavy asbestos/cement pipes are used.
An objective of the present invention is to provide an improved mechanism which is simple and inexpensive in its construction, and which may be used in a narrow trench to draw aligned pipes into coupling engagement with one another, and which fulfills all the criteria outlined in the preceding paragraphs, and which reduces to a minimum the number of workmen required to assemble the pipeline.